Gary Johnson, the Libertarian Party’s nominee for president of the United States, is being mercilessly ridiculed for asking what Aleppo was when Morning Joe host Mike Barnicle mentioned the Syrian city on Thursday morning. But I’m grateful to Johnson. Many politicians in that situation would pretend they were familiar with Aleppo and then pivot to a more comfortable topic. (“Aleppo is, of course, a very serious issue that as president I would seek to address. But I gotta say: My top priority would be stopping wasteful government spending. That’s really the greatest threat to our national security,” etc.)

As a candidate for America’s highest office, Johnson should know what Aleppo is. But he’s certainly not alone in not knowing. And had he not asked the question, #WhatIsAleppo wouldn’t be trending on Twitter. BuzzFeed wouldn’t be asking its readers to find Aleppo on a map. People might not be discussing how Matt Lauer barely brought up Syria during NBC’s Commander in Chief Forum on Wednesday. We wouldn’t be talking as much about something we should be talking about more: the epicenter of Syria’s civil war and humanitarian crisis.

Aleppo is one of the oldest continuously inhabited cities on earth. It was once Syria’s vibrant commercial capital, and for the first year of the Syrian uprising against President Bashar al-Assad it remained relatively peaceful. But in July 2012, government and rebel forces began doing battle there. Aleppo and the Syrian political capital of Damascus “had been the two significant holdouts in the fighting that has gradually engulfed the rest of Syria,” The New York Times observed at the time. “[N]ow the whole country is inflamed. … Whoever controls the two jewels-in-the-crown controls Syria.”

In the past four years, Aleppo—particularly rebel-held eastern Aleppo—has been bombarded, besieged, and drained of many of its people, who have either been killed or forced to flee. Food, water, medicine, and life’s other essentials are scarce, and aid organizations have struggled to gain access to the city. Medical facilities have been repeatedly attacked by suspected Syrian and Russian fighter jets, and the population of doctors is dwindling fast; in April, one of the last pediatricians in Aleppo died in an air strike. Aleppo is where ceasefires go to die. It’s a witness to the horror of barrel bombs and alleged chemical-weapons attacks. It’s also where a dazed, bloody five-year-old boy, Omran Daqneesh, was recently pulled from a bombed building and placed in an ambulance, as his image reverberated around the world.

The remaining residents of Aleppo are split between government- and opposition-controlled sections of the city, as Lina Sergie Attar, an Aleppo native who now lives in America, noted in August, after an array of rebel groups briefly breached Assad’s siege:

A favorite tool of the dispassionate Syria analyst is a map: red and green blobs showing a shifting front line, which streets are held by rebels and which by the government. These wretched maps rudely superimpose their lines over the landmarks of my life: On the east are the people I grew to love through the revolution, men, women and children who defied all odds and stood chanting in the face of one of the most ruthless regimes in history. On the west are my streets, my school, my university, my home. ...

When I watch footage from Ramouseh, the southwestern district where the siege was broken, I turn my eyes away from the bearded men with guns and instead marvel at the rich red soil, which for centuries has nurtured Aleppo’s famous olives, pistachios and sour cherries. In videos of people in eastern Aleppo celebrating their relief from the siege, I scan the row of limestone buildings and count the undamaged facades, finding hope in each one.

The shifting battle lines in Aleppo—those red and green blobs—matter, because the outcome of the Syrian Civil War, and thus related crises like the fight against ISIS and the outflow of Syrian refugees to other countries in the Middle East and Europe, could hinge on them. As Andrew Tabler of the Washington Institute for Near East Policy told my colleague Kathy Gilsinan earlier this year, if Aleppo were to fall to the Syrian government, it could “cement the regime’s hold on ‘essential Syria’. … [Y]ou would have the regime presence from Aleppo the whole way down to Hama, Homs, and Damascus, and that’s the spine of the country, and that’s what concerns the regime and the Iranians in particular. It would then allow them to free up forces, potentially, to go on the offensive elsewhere, directly into Idlib province, most likely, and then eventually into the south. Then after that they could turn their attention finally to ISIS.”

If Assad, along with his Russian and Iranian allies, were to emerge victorious in Aleppo, it would have consequences beyond Syria, Tabler added: “It would be a tremendous loss for the U.S. and its traditional allies: Turkey, Saudi Arabia, Qatar, and Jordan. … This would also be a huge loss for the United States vis-à-vis Russia in its Middle East policy, certainly. And because of the flow of refugees as a result of this, if they go northward to Europe, then you would see a migrant crisis in Europe that could lead to far-right governments coming to power which are much more friendly to Russia than they are to the United States.” In other words, to answer Gary Johnson’s question, Aleppo is a lot more than a Syrian city.